Vandelliinae: The Blood-Feeding Parasitic Catfishes
Within the diverse world of freshwater ray-finned fishes, the Vandelliinae stand out as one of the most specialized groups. Belonging to the family Trichomycteridae—commonly known as pencil and parasitic catfishes—these creatures have evolved a highly specific survival strategy: hematophagy, the practice of feeding on blood.
Often referred to by the common name candirú, these fish are primarily known for their parasitic relationship with other aquatic species. While they have gained notoriety in popular culture for rare interactions with humans, their biological role is far more focused on the complex ecosystems of their native freshwater habitats.
[ไม่มีภาพประกอบ]Key Facts
- Diet: Hematophagous (feeds exclusively on blood).
- Family: Trichomycteridae (pencil and parasitic catfishes).
- Primary Hosts: Ostariophysan fishes, including characins, doradids, and pimelodids.
- Key Feature: Relatively large eyes compared to other catfish species, suggesting a reliance on sight for prey detection.
- Behavior: Enters the body cavities of host fish to feed on blood from gill filaments.
Biological Classification and Genera
The Vandelliinae subfamily is categorized under the order Siluriformes. The group is composed of several distinct genera that share the parasitic trait. The type genus for this subfamily is Vandellia, established by Valenciennes in 1846.
Classified Genera
The subfamily currently includes the following four genera:
- Vandellia (Valenciennes, 1846)
- Paravandellia (A. Miranda-Ribeiro, 1912)
- Plectrochilus (A. Miranda Ribeiro, 1917)
- Paracanthopoma (Giltay, 1935)
Feeding Behavior and Ecology
Vandelliines are specialized parasites that target ostariophysan fishes—a large superorder of fishes that includes various catfish and carps. Specifically, they often target pimelodids, doradids, and characins.
The typical feeding process involves the candirú entering the body cavities of a host fish. Once inside, the parasite feeds on the blood found within the gill filaments before exiting the host. To facilitate this process, these fish possess relatively large eyes, which indicates that visual cues are likely critical for locating and detecting potential hosts in the water.
The Human Interaction Myth
The candirú is notorious for reports of entering human bodily orifices, most notably the urethra. However, scientific evidence suggests that such occurrences are rare and accidental aberrations of their natural feeding behavior. Because the human body is not a natural host, it is unlikely the fish could survive for long, making such events disastrous for both the human and the fish.
| Feature | Description |
|---|---|
| Scientific Name | Vandelliinae |
| Feeding Type | Hematophagous (Blood-feeding) |
| Common Name | Candirú |
| Primary Target | Gill filaments of host fishes |
| Visual Adaptation | Large eyes for prey detection |
Frequently Asked Questions
What does hematophagous mean?
Hematophagous refers to organisms that feed on blood as their primary source of nutrition.
Which fish do Vandelliines typically parasitize?
They usually parasitize ostariophysan fishes, such as characins, doradids, and pimelodids.
Do candirú fish intentionally attack humans?
No. There is no evidence to suggest they intentionally target humans; reports of them entering human orifices are considered rare and accidental aberrations of their normal behavior.
How do these fish find their hosts?
Vandelliines have relatively large eyes compared to other catfishes, which suggests that sight plays an important role in detecting their prey.
Where do they feed on the host fish?
They typically enter the body cavities of the host fish and feed on the blood from the gill filaments.